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7. Hand and Wrist MCQs

Practice Set 121 of 266

This practice set contains high-yield board review questions covering key concepts in 7. Hand and Wrist. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 2401

Topic: Nerve & Tendon

A 9-year-old boy falls off monkey bars and presents with forearm pain. Radiographs demonstrate a fracture of the proximal third of the ulna and an anterior dislocation of the radial head. Which nerve is most commonly injured in this specific fracture-dislocation pattern?

. Median nerve
. Anterior interosseous nerve
. Posterior interosseous nerve
. Ulnar nerve
. Musculocutaneous nerve

Correct Answer & Explanation

. Posterior interosseous nerve

Explanation

This is a Monteggia fracture-dislocation. The radial head dislocation (especially anterior or lateral) can stretch or directly injure the Posterior Interosseous Nerve (PIN), leading to weakness in finger and thumb extension.

Question 2402

Topic: 7. Hand and Wrist

A 65-year-old man presents with bilateral hand weakness and numbness after a hyperextension injury. He is able to ambulate but struggles to button his shirt. What is the most likely anatomic location of the primary spinal cord injury?

. Anterior horn cells
. Dorsal columns
. Central gray matter and medial corticospinal tracts
. Lateral spinothalamic tracts
. Anterior spinocerebellar tract

Correct Answer & Explanation

. Central gray matter and medial corticospinal tracts

Explanation

Central cord syndrome typically occurs after hyperextension injuries in stenotic cervical canals. The medial location of the cervical tracts in the corticospinal tract leads to disproportionate upper extremity weakness, particularly distal hand function.

Question 2403

Topic: 7. Hand and Wrist
A 65-year-old male presents with bilateral upper extremity weakness (hands > arms) and mild lower extremity weakness after a hyperextension injury. Which of the following is true regarding his prognosis?
. Lower extremities will recover last
. Hand intrinsic function is the least likely to fully recover
. Bladder dysfunction is typically permanent
. He will likely require early surgical decompression to improve neurologic recovery
. Prognosis for independent ambulation is poor

Correct Answer & Explanation

. Hand intrinsic function is the least likely to fully recover

Explanation

In central cord syndrome, the classic recovery pattern progresses from the lower extremities to the upper extremities, and from proximal to distal. Hand intrinsic function is the last to return and the least likely to fully recover.

Question 2404

Topic: 7. Hand and Wrist

A 68-year-old man with known cervical spondylosis presents after a hyperextension injury. He has significant upper extremity weakness (motor grade 2/5) but is able to move his lower extremities (grade 4/5). Sensation is variably diminished below the neck. Which of the following is the most likely prognosis for his neurologic recovery?

. Good prognosis for fine motor skills of the hands
. Complete recovery within 6 weeks
. Good prognosis for lower extremity recovery, but poor for fine motor skills of the hands
. Progressive deterioration without emergent surgical decompression
. Loss of bowel and bladder function is permanent

Correct Answer & Explanation

. Good prognosis for lower extremity recovery, but poor for fine motor skills of the hands

Explanation

This patient has a central cord syndrome. The typical recovery pattern involves the lower extremities recovering first and most completely, while upper extremity fine motor function often remains impaired.

Question 2405

Topic: 7. Hand and Wrist

A 45-year-old woman complains of right neck pain radiating down the arm. Examination shows weakness of triceps extension and wrist flexion, with an absent triceps reflex. Sensation is decreased over the middle finger. Which cervical nerve root is most likely compressed?

. C5
. C6
. C7
. C8
. T1

Correct Answer & Explanation

. C7

Explanation

The C7 nerve root is responsible for triceps and wrist flexor motor function, the triceps reflex, and sensation over the middle finger. Compression typically occurs at the C6-C7 disc level.

Question 2406

Topic: 7. Hand and Wrist
A newborn is noted to have a hemivertebra at T8 causing a mild congenital scoliosis. Which of the following screening tests is mandatory in the initial evaluation of this patient?
. Renal ultrasound
. Pulmonary function tests
. Brain MRI
. DEXA scan
. Genetic testing for FBN1 mutation

Correct Answer & Explanation

. Renal ultrasound

Explanation

Congenital scoliosis is highly associated with VACTERL anomalies, particularly genitourinary and cardiovascular defects. A renal ultrasound and an echocardiogram are mandatory screening tests to rule out associated visceral anomalies.

Question 2407

Topic: 7. Hand and Wrist

An 80-year-old man falls and strikes his chin, hyperextending his neck. He presents with 2/5 strength in his upper extremities and 4/5 strength in his lower extremities. Sensation is decreased in the hands. Reflexes are brisk in the lower extremities. Which of the following is the most accurate prognostic statement regarding his neurologic recovery?

. Hand intrinsic muscle function is typically the first to recover
. He has a poor prognosis for independent ambulation
. Motor recovery generally occurs in a distal to proximal pattern
. Hand intrinsic function often remains persistently impaired despite overall improvement
. Surgical decompression is strictly contraindicated in this condition

Correct Answer & Explanation

. Hand intrinsic function often remains persistently impaired despite overall improvement

Explanation

The patient has central cord syndrome, characterized by greater weakness in the upper extremities than the lower extremities. The typical pattern of recovery is lower extremities first, followed by proximal upper extremities, with distal hand intrinsic function often remaining permanently impaired.

Question 2408

Topic: 7. Hand and Wrist

A 42-year-old man complains of right neck and arm pain. Physical examination reveals weakness in wrist extension, a diminished brachioradialis reflex, and numbness over the dorsal thumb and index finger. Which cervical nerve root is most likely compressed?

. C5
. C6
. C7
. C8
. T1

Correct Answer & Explanation

. C6

Explanation

Compression of the C6 nerve root presents with weakness in wrist extension and elbow flexion, a diminished brachioradialis reflex, and sensory changes in the thumb and index finger.

Question 2409

Topic: 7. Hand and Wrist

Following anatomic rigid internal fixation of the radius in a Galeazzi fracture, the distal radioulnar joint (DRUJ) remains irreducible. Which structure is most likely interposing and blocking reduction?

. Extensor carpi ulnaris tendon
. Extensor carpi radialis brevis tendon
. Flexor carpi radialis tendon
. Median nerve
. Brachioradialis tendon

Correct Answer & Explanation

. Extensor carpi ulnaris tendon

Explanation

In Galeazzi fracture-dislocations, an irreducible DRUJ is typically caused by interposition of the extensor carpi ulnaris (ECU) tendon. Less commonly, the median or ulnar nerve can become entrapped.

Question 2410

Topic: Wrist & Carpus
In the natural history of Scapholunate Advanced Collapse (SLAC), Stage III arthritic changes classically involve which of the following articulations?
. Radioscaphoid joint
. Radiolunate joint
. Capitolunate joint
. Scaphotrapezial joint
. Distal radioulnar joint

Correct Answer & Explanation

. Radiolunate joint

Explanation

SLAC progresses in predictable stages: Stage I involves the radial styloid, Stage II encompasses the entire radioscaphoid joint, and Stage III progresses to the capitolunate joint. The radiolunate joint is characteristically spared due to the concentric shape of the lunate fossa.

Question 2411

Topic: Wrist & Carpus

A 24-year-old male presents with a proximal pole scaphoid fracture. You elect to proceed with percutaneous screw fixation. Which surgical approach and screw trajectory offer the best mechanical advantage and easiest access for a proximal pole fracture?

. Volar approach, distal to proximal trajectory
. Dorsal approach, proximal to distal trajectory
. Volar approach, proximal to distal trajectory
. Dorsal approach, distal to proximal trajectory
. Radial snuffbox approach, central trajectory

Correct Answer & Explanation

. Dorsal approach, proximal to distal trajectory

Explanation

Proximal pole scaphoid fractures are best approached dorsally to allow a proximal-to-distal screw trajectory. This approach minimizes damage to the precarious blood supply entering distally and allows central placement of the screw in the small proximal fragment.

Question 2412

Topic: 7. Hand and Wrist
According to Mayfield's stages of perilunate instability, what is the defining pathoanatomy of the final stage (Stage IV)?
. Disruption of the scapholunate ligament
. Dislocation of the capitate dorsally
. Disruption of the lunotriquetral ligament
. Volar dislocation of the lunate into the carpal tunnel
. Dorsal perilunate dislocation

Correct Answer & Explanation

. Volar dislocation of the lunate into the carpal tunnel

Explanation

Mayfield Stage IV represents a complete lunate dislocation, where the dorsal radiocarpal ligaments fail, and the lunate is extruded volarly into the carpal tunnel. Stage I is scapholunate failure, Stage II is capitate dislocation, and Stage III is lunotriquetral failure.

Question 2413

Topic: Wrist & Carpus

A 28-year-old male sustains a Galeazzi fracture. Following open reduction and internal fixation of the radial shaft, the distal radioulnar joint (DRUJ) remains grossly unstable in all forearm positions. What is the most appropriate first step in management?

. Long arm casting in neutral rotation
. Open repair of the triangular fibrocartilage complex (TFCC)
. Transfixing the DRUJ with K-wires for 4 to 6 weeks
. Distal ulna resection
. Re-evaluating the radial reduction for malrotation or shortening

Correct Answer & Explanation

. Re-evaluating the radial reduction for malrotation or shortening

Explanation

In a Galeazzi fracture, the most common cause of persistent DRUJ instability after fixation of the radius is non-anatomic reduction (shortening or malrotation) of the radial shaft. The surgeon must first re-evaluate and perfectly correct the radius fixation before addressing the TFCC directly or pinning the joint.

Question 2414

Topic: Wrist & Carpus

A 55-year-old woman presents with sudden inability to actively flex the interphalangeal joint of her thumb. She underwent volar locked plating for a distal radius fracture 6 months ago. What is the most likely anatomical etiology of this complication?

. EPL tendon rupture from dorsal screw prominence
. FPL tendon rupture from plate prominence distal to the watershed line
. Anterior interosseous nerve palsy from surgical traction
. FDP tendon rupture from prominent ulnar screws
. Adhesions of the FCR tendon within its sheath

Correct Answer & Explanation

. FPL tendon rupture from plate prominence distal to the watershed line

Explanation

Placement of a volar plate distal to the watershed line of the distal radius can cause mechanical attrition and subsequent rupture of the flexor pollicis longus (FPL) tendon. The watershed line marks the safe distal limit for hardware placement.

Question 2415

Topic: 7. Hand and Wrist
According to Mayfield's stages of perilunate instability, what structural failure characterizes the transition from a Stage III (perilunate dislocation) to a Stage IV (lunate dislocation)?
. Tear of the scapholunate interosseous ligament
. Tear of the lunotriquetral interosseous ligament
. Tear of the dorsal radiocarpal ligament allowing the lunate to spill volarly
. Tear of the short volar radiolunate ligament
. Rupture of the radioscaphocapitate ligament

Correct Answer & Explanation

. Tear of the dorsal radiocarpal ligament allowing the lunate to spill volarly

Explanation

In Mayfield Stage IV, the dorsal radiocarpal ligament fails. The lunate then rotates volarly into the carpal tunnel, hinging on the intact short volar radiolunate ligament, resulting in a classic lunate dislocation.

Question 2416

Topic: Wrist & Carpus
A 50-year-old male presents with chronic wrist pain and a history of remote trauma. Radiographs reveal advanced arthritis of the radioscaphoid and capitolunate joints, with sparing of the radiolunate joint. This radiographic pattern is highly characteristic of which stage of Scapholunate Advanced Collapse (SLAC)?
. Stage I
. Stage II
. Stage III
. Stage IV
. SNAC Stage II

Correct Answer & Explanation

. Stage III

Explanation

SLAC Stage III is characterized by arthritic changes in the radioscaphoid and capitolunate joints. The radiolunate joint is typically spared due to the concentric, purely spherical articulation that does not develop abnormal shear forces.

Question 2417

Topic: Wrist & Carpus

A 35-year-old male undergoes ORIF of the radius for a distal-third radial shaft fracture with associated distal radioulnar joint (DRUJ) instability (Galeazzi fracture). Intraoperatively, after anatomic radius fixation, the DRUJ remains grossly irreducible in all forearm positions. What is the most appropriate next step?

. Immobilize the forearm in full pronation
. Percutaneous pinning of the DRUJ
. Open exploration of the DRUJ to remove interposed tissue
. Darrach procedure (distal ulna resection)
. Arthroscopic repair of the triangular fibrocartilage complex (TFCC)

Correct Answer & Explanation

. Open exploration of the DRUJ to remove interposed tissue

Explanation

If the DRUJ remains irreducible after anatomic restoration of the radius in a Galeazzi fracture, open exploration is required. The most common cause is soft tissue interposition, typically the extensor carpi ulnaris (ECU) tendon.

Question 2418

Topic: Wrist & Carpus

A 55-year-old female undergoes volar locked plating for a distal radius fracture. Six weeks postoperatively, she suddenly loses the ability to actively extend her thumb interphalangeal joint. What is the most likely iatrogenic cause of this complication?

. Prominent volar plate placement distal to the watershed line
. Dorsal screw penetration into the third extensor compartment
. Intraoperative transection of the posterior interosseous nerve
. Loss of radial height causing attritional wear
. Failure to repair the pronator quadratus

Correct Answer & Explanation

. Dorsal screw penetration into the third extensor compartment

Explanation

Rupture of the extensor pollicis longus (EPL) tendon following volar plating of the distal radius is most frequently caused by prominent screws penetrating the dorsal cortex into the third extensor compartment.

Question 2419

Topic: 7. Hand and Wrist

A 32-year-old male falls on an extended, ulnarly deviated wrist. Radiographs demonstrate a 'spilled teacup' sign on the lateral view and overlapping carpal arcs on the PA view. According to Mayfield's stages of perilunate instability, which structure is the first to fail in this cascade?

. Lunotriquetral ligament
. Dorsal radiocarpal ligament
. Scapholunate ligament
. Volar radiolunate ligament
. Radioscaphocapitate ligament

Correct Answer & Explanation

. Scapholunate ligament

Explanation

Mayfield's cascade of perilunate instability occurs in four stages, beginning radially and progressing ulnarly. The scapholunate ligament is the first structure to fail (Stage I).

Question 2420

Topic: Nerve & Tendon

A 50-year-old female requires dual plating for a severely comminuted intra-articular distal humerus fracture (AO/OTA 13C3). Based on current orthopedic consensus, what is the recommended management of the ulnar nerve during this procedure?

. Routine anterior subcutaneous transposition is mandatory
. In situ decompression is preferred unless hardware impingement requires transposition
. Submuscular transposition must be performed to avoid neuroma
. Excision of the medial epicondyle to relieve tension
. The nerve should remain unexposed to prevent devascularization

Correct Answer & Explanation

. In situ decompression is preferred unless hardware impingement requires transposition

Explanation

Current evidence suggests that routine anterior transposition of the ulnar nerve is unnecessary and may increase the risk of neuritis. In situ decompression is preferred, with transposition reserved for cases where the nerve subluxates or rubs against implants.

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